Methyl isothiocyanate

Methyl isothiocyanate
Names
IUPAC name
Methylisothiocyanate
Other names
MITC
Identifiers
556-61-6 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:78337 N
ChEMBL ChEMBL396000 YesY
ChemSpider 10694 YesY
ECHA InfoCard 100.008.303
KEGG C18587 N
PubChem 11167
Properties
C2H3NS
Molar mass 73.12
Appearance colourless solid
Density 1.07 g cm−3
Melting point 31 °C (88 °F; 304 K)
Boiling point 117 °C (243 °F; 390 K)
8.2g/L
Hazards
Safety data sheet ACC# 07204
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
1
3
1
Structure
3.528 D
Related compounds
Related compounds
 Methyl isocyanate
Methyl thiocyanate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Methyl isothiocyanate is the organosulfur compound with the formula CH3N=C=S. This low melting colorless solid is a powerful lachrymator. As a precursor to a variety of valuable bioactive compounds, it is the most important organic isothiocyanate in industry.[1]

Synthesis

It is prepared industrially by two routes. Annual production in 1993 was estimated to be 4M kg. The main method involves the thermal rearrangement of methyl thiocyanate:[1]

CH3S-C≡N → CH3N=C=S

It is also prepared via with the reaction of methylamine with carbon disulfide followed by oxidation of the resulting dithiocarbamate with hydrogen peroxide. A related method is useful to prepare this compound in the laboratory.[2]

MITC forms naturally upon the enzymatic degradation of glucocapparin, a modified sugar found in capers.

Reactions

A characteristic reaction is with amines to give methyl thioureas:

CH3NCS + R2NH → R2NC(S)NHCH3

Other nucleophiles add similarly.

Applications

Solutions of MITC are used in agriculture as soil fumigants, mainly for protection against fungi and nematodes.

MITC is a building block for the synthesis of 1,3,4-thiadiazoles, which are heterocyclic compounds used as herbicides. Commercial products include "Spike", "Ustilan," and "Erbotan."

Well known pharmaceuticals prepared using MITC include Zantac and Tagamet. Suritozole is a third example.

MITC is used in the Etasuline patent (Ex2[3]), although the compound is question (Ex6) is with EITC.

Safety

MITC is a dangerous lachrymator as well as being poisonous.

References

  1. 1 2 Romanowski, F.; Klenk, H. (2005), "Thiocyanates and Isothiocyanates, Organic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a26_749
  2. ↑ Moore, M. L.; Crossley, F. S. (1941). "Methyl Isothiocyanate". Org. Synth. 21: 81.; Coll. Vol., 3, p. 599
  3. ↑ U.S. Patent 3,417,085
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